Low Roll-Off and High Stable Electroluminescence in Three-Dimensional FAPbI<sub>3</sub> Perovskites with Bifunctional-Molecule Additives
Hao Zhang, Cailing Tu, Chen Xue, Jianhong Wu, Yu Cao, Wei Zou, Wenjie Xu, Kaichuan Wen, Zhang Ju, Yu Chen, Jingya Lai, Lin Zhu, Kang Pan, Lei Xu, Yingqiang Wei, Hongzhen Lin, Nana Wang, Wei Huang, Jianpu Wang
Abstract
Three-dimensional (3D) perovskites have been demonstrated as an effective strategy to achieve efficient light-emitting diodes (LEDs) at high brightness. However, most 3D perovskite LEDs still suffer from serious efficiency roll-off. Here, using FAPbI3 as a model system, we find that the main reason for efficiency droop and degradation in 3D perovskite LEDs is defects and the ion migration under electrical stress. By introducing bifunctional-molecule 3-chlorobenzylamine additive into the perovskite precursor solution, the detrimental effects can be significantly suppressed through the growth of high crystalline perovskites and defect passivation. This approach leads to bright near-infrared perovskite LEDs with a peak external quantum efficiency of 16.6%, which sustains 80% of its peak value at a high current density of 460 mA cm–2, corresponding to a high brightness of 300 W sr–1 m–2. Moreover, the device exhibits a record half-lifetime of 49 h under a constant current density of 100 mA cm–2.